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    • Efficiency difference - Single turbo N54 on 93 octane with port injection only at 27 psi vs. E40 with direct injection only at 22 psi making similar power

      This is a very interesting dyno overlay. The car is an E92 335i N54 with a Garrett Gen2 3582R single turbo conversion. The difference you see between the two pulls on the Dynojet graph below is due to the fuel, injection type, and boost pressure.


      On 93 octane with port injection at 27 psi the car makes 575 horsepower and 575 lb-ft of torque at the wheels.

      On E40 ethanol without port injection and with an upgraded LPFP (low pressure fuel pump) the car makes 576 wheel horsepower and 585 lb-ft of torque at the wheels at 22 psi of boost:


      That is a large difference in efficiency.

      For further context it would be great to see ethanol through the port fuel injection system only at the same boost level as the direct injection system.

      More data would only help but this is a great demonstration of octane, fueliing, boost, and efficiency.

      This article was originally published in forum thread: Efficiency difference - Single turbo N54 on 93 octane with port injection only at 27 psi vs. E40 with direct injection only at 22 psi making similar power started by Sticky View original post
      Comments 15 Comments
      1. Payam@BMS's Avatar
        Payam@BMS -
        Wish there was a log for each run Click here to enlarge
      1. maxnix's Avatar
        maxnix -
        Just adding 93 E10 with PI?
      1. Sticky2's Avatar
        Sticky2 -
        Click here to enlarge Originally Posted by Payam@BMS Click here to enlarge
        Wish there was a log for each run Click here to enlarge
        Yep very superficial but interesting nonetheless.
      1. crapinternet's Avatar
        crapinternet -
        I WANT MORE ETHANOL IN MY FUEL!
      1. 135idct's Avatar
        135idct -
        i think the timing is very low on pmup93 at 27psi
      1. CobraMarty's Avatar
        CobraMarty -
        93oct, PI, 27psi =power= E40, DI, 22psi

        So does this mean DI is more efficient than PI in making power? Or is it the 93oct vs E40?

        Isn't that the point of DI, more efficiency.
      1. lvevo's Avatar
        lvevo -
        I thought DI was used to be more fuel efficient. Less fuel is needed in DI than PI.
      1. MDORPHN's Avatar
        MDORPHN -
        Isn't this really due to being able to run more timing with the E40?

        Neil
      1. tisdrew2's Avatar
        tisdrew2 -
        Click here to enlarge Originally Posted by MDORPHN Click here to enlarge
        Isn't this really due to being able to run more timing with the E40?

        Neil
        While you can run more timing, the boost difference is the differentiator here. Without knowing the exact timing of each, we won't know what contributed to the numbers directly.
      1. Bowser330's Avatar
        Bowser330 -
        The different ethanol content adds another variable that makes it harder to compare PI vs. DI.

        Why not run 93 (E10) on the DI system @ 22psi to see the real efficiency difference?
      1. Sticky2's Avatar
        Sticky2 -
        Click here to enlarge Originally Posted by Bowser330 Click here to enlarge
        The different ethanol content adds another variable that makes it harder to compare PI vs. DI.

        Why not run 93 (E10) on the DI system @ 22psi to see the real efficiency difference?
        It is odd they would take the time to do this yet not provide all the data or try to minimize variables. Why even bother?
      1. Sticky2's Avatar
        Sticky2 -
        Click here to enlarge Originally Posted by lvevo Click here to enlarge
        I thought DI was used to be more fuel efficient. Less fuel is needed in DI than PI.
        What? The DI example will need more fuel due to the ethanol content.
      1. Weehe's Avatar
        Weehe -
        Pretty sure his point was that you can be leaner with DI, with either 93 or E40, safer. Obviously E40 would have a higher fuel volume.
      1. Eleventeen's Avatar
        Eleventeen -
        Timing plays a huge role in power production, so as others have mentioned, this could be the biggest factor. It is definitely possible to lower boost, but make more power by increasing timing (which they can do with more ethanol and DI). Need to see logs, otherwise this is just "apples to oranges". That being said, DI is definitely more efficient.

        The other thing is, on this engine, the GT3582R is going to be more efficient at 22psi vs. 27psi. That turbo doesn't have a very big exhaust turbine.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by Weehe Click here to enlarge
        Pretty sure his point was that you can be leaner with DI, with either 93 or E40, safer. Obviously E40 would have a higher fuel volume.
        Not sure how that would apply to the topic with ethanol used in DI but you can be leaner on pump fuel at low load.

        If WOT and full boost all the time you won't see a measurable difference when you can't lean the car out safely.